Comparing 2 spreadsheets

Thanks in advance for any assistance.
Let's say I have 2 separate spreadsheets. Spreadsheet A has these columns: Customer ID, August sales. Spreadsheet B has: Customer ID, Sept sales. I would like to quickly compare the two sheets by Customer ID. For example, line up Spreadsheet A!Customer ID with Spreadsheet B!Customer ID and have August sales and September sales on the same row.
(What I do now is use MS Access to accomplish this very same task.)